Welcome to the Gears of War's sandbox!
This page exists so that you can practice editing or formatting (see Editing help) without changing any serious content. Feel free to try wiki editing out here first.
There is a tutorial on the Central (coordinating) Wikia that will step you through more of the things you can do. Wiki allow for rather complicated formatting. It can look overwhelming when you begin, but don't let it worry you. Just start with the basics... enter some text, and learn the other pieces as you go. Your content contributions are welcome and important. The wiki is a collaborative effort and others can help with formatting and other improvements.
Shouldn't there be a Savage Sniper? No because how would a sniper be savage if it was then it would be awful Edit
Wouldn't it be great to go to the Lancer Assault Rifle page, and see the differences between the Gears 1 rifle, and the Gears 2 rifle clearly itemized, with maybe some specific weapon data for each (similar to the level of detail you'd see in an advanced fighting game guide)?
Or maybe finding out how the retro lancer is called the Retro lancer?
A quick visit to the Mk1 Lancer page, will answer a few of your questions.